declare @inputDate as nvarchar(12) = '201908291250'
declare @year as nvarchar(4) = substring(@inputDate, 1, 4)
declare @month as nvarchar(2) = substring(@inputDate, 5, 2)
declare @day as nvarchar(2) = substring(@inputDate, 7, 2)
Declare @hours as nvarchar(2) = substring(@inputDate, 9, 2)
declare @minutes as nvarchar(2) = substring(@inputDate, 11, 2)
select convert(datetime, @year + '-' + @month + '-' + @day + ' ' + @hours + ':' + @minutes, 20)